The brook became smaller and narrower, and at the end of the night it was less than a yard across. The next evening they left the rushes in the wet ground where they had been sleeping, and crossing a road, came to a boggy tract where curlew and snipe lived. Tarka ran over the line of a hare, and followed it in curiosity until his mother called him back. Mosses made the way soft and held many scents--of marsh orchid, stinking iris, bog pimpernel; of wild duck, stoat, short-eared owl, magpie, and, once the rank-smelling flight-quill of a raven. They reached a thread of water and followed it downward until it was joined by another thread. The two made a stream, which hastened under whitish banks of clay. The otter sought for fish, but finding none, climbed out of the channel by a slanting otter-path and crossed the railway track near a tall, dark chimney that rose out of buildings. It was a brick factory. An otter had travelled before them, and in a hollow behind birch trees about a quarter of a mile on they heard a whistle; and running towards the call, they came to a deep reed-fringed pond, on the clay side of which a grown dog-otter was playing with the wings of a drake. Tarka kept behind his mother, being frightened of the stranger. He had a split ear, done in a fight two years before. Mother and cubs went into the pond, leaving him rolling on the bank and tossing the wings with his paws. The pond was an old pit from which white clay had been dug. The water was deeper than any the cubs had swum in. Round the edge grew reed-maces; it was early June and the golden fountains of pollen were spilling on the green heads, which would be brown in autumn. Ten ducklings were hiding in the reeds, while their mother circled in the starry sky, telling them, with soft cries of _quaz-qua-a-a-az-quaz_, not to move. She had flown up when the dog-otter had caught and eaten the drake, swimming up underneath it. At the time of capture the drake had been trying to swallow a frog, by quapping with its bill, which held one of the legs. When the otter's teeth had gripped the drake, the frog had escaped; but it commenced to swell on the water and so it could not swim down to the pit's floor. Tarka saw it above him as he pushed about eagerly under water: the frog showed darkly in the dim surface mirror which reflected the grey sludge of the pond's bed. Tarka caught it, and ate it under a thorn bush planted by a thrush beside the pond.